1. Field of the Invention
The present invention relates generally to optical image scanners and more particularly to facilitating manual removal of an object from a scanner.
2. Description of the Related Art
With reference to FIGS. 1–3, there is shown in schematic form portions of a conventional flatbed scanner 10 comprising a generally rectangular housing 12 extending along a longitudinal direction 14. The housing 12 supports a transparent platen 16 comprising a planar, object-supporting top surface 18 defining the image plane of an object 20 to be scanned. The object 20 may take many forms but will typically comprise a photograph, transparency or a document.
The scanner housing 12 comprises a top wall 22, opposed side walls 24, and front and back walls 26 and 28, respectively. The top wall 22 of the housing comprises an upper surface 30 framing a generally rectangular opening or window 32 formed in the top wall 22. The window 32 is defined by vertical edges such as the edge 34 shown in FIG. 2 channeled to receive and securely retain the perimeter 36 of the platen 16. It will be seen that the representative vertical edge 34 has an upper vertical edge portion 38 extending upwardly from the object-supporting top surface 18 of the platen.
During reflective scanning, the lower surface of the document is illuminated along a transverse linear strip or scan line by a light source on an object-imaging device mounted under the platen for movement from front to back. A beam of light reflected from the illuminated scan line passes through a light-receiving aperture in the object-imaging device to a photodetector array via a system of mirrors. The photodetector array may comprise a linear CCD for converting the image of the object into a digital electronic image.
As shown in FIG. 3, when an attempt is made to remove the document 20 from the scanner by sliding it off the platen across the edge 34 of the window, the upper vertical edge portion 38 intercepts an edge 40 of the document 20 and thus interferes with the removal of the document. To avoid this, the user often needs to pry up an edge of the document with a fingernail so as to raise a margin which can be gripped and the document thereby removed clear of the obstructing window edge. This can be a time-consuming, annoying operation that, in addition, may damage the document.